A projector or image projector is an optical device that projects a picture (or transferring images) onto a surface, generally a projection screen. Most projectors make an image by shining a light through a tiny transparent lens, but some newer kinds of projectors can project the picture directly, using lasers. A virtual retinal display, or retinal projector, is a projector that projects an image directly on the retina instead of using an external projection screen.
The most typical type of projector used today is referred to as a movie projector. Video projectors are digital replacements for earlier types of projectors like slide projectors and overhead projectors. These earlier kinds of projectors were mostly replaced with electronic video recorders through the 1990s and early 2000s, but outdated analog projectors continue to be used in some areas. The newest types of projectors are handheld projectors which use lasers or LEDs to project pictures. Their projections are tough to see whether there is too much ambient lighting.
Film theaters utilized a sort of projector called a film projector, nowadays mostly replaced with digital cinema video projectors.